I learned from the Deals forum here that the Ringworld audio book was offered as a giveaway from Downpour.com recently, so I grabbed it. I enjoyed it, and am now in the middle of Ringworld Engineers, because there were a number of questions I wanted answers to, but I doubt I'll be compelled to put many other Ringworld books high on my TBR list.
One thing about the audiobook, if not for seeing it written earlier in this thread, I'd NEVER have realized that "Tanj" was an acronym!
And another thing about the Ringworld books:
Boy, those folks sure like their rishathra, don't they? Not that there's anything wrong with that....